Method for treating tobacco



WIM

R. D. T ouToN METHOD FOR TREATING TOBACCO Filed April 11, 1935 1. l J J l m fl E www Jan. 18, 1938.

Patented Jan. i8, 1938 UNITED srarns escasas s Tomwoo lTENT orifice METHOD FOB Application apra n, 193s, serial N0. 15,181

' s claims. (ci. 3;-24)

This invention relates to a method and apparatus for treating tobacco and more particularly to amethod for finally preparing tobacco for use in the manufacture of cigars. f

As is well known, tobacco after harvesting is cured and packed in the form of bunches or hands in bales for shipment. When received by the fabricator the tobacco is dry and must be moistened to enable separation of the leaves forming the bunches or hands and to enable stripping or removal of the stems without injury to the leaves. Separation and stripping having been accomplished, it is necessary, as is well known, to reduce the moisture content of the tobacco prior to its fabrication, in order that the vnished product, as a cigar, will have a 'proper and desired moisture content for use.

Heretofore,it has been customaryto moisten tobacco in various ways in order to enableseparation of the leaves and stripping, and then, after stripping, to effect reduction of the moisture content to a desired point for fabricationv by subjecting the tobaccoin pads comprising a plurality of leaves, to a dry', heated atmosphere for f reducing the moisture content thereof prior to a requisite time.

'I'he procedure for reducing the vmoisture content of tobacco prior to fabrication as heretofore known has been found unsatisfactory'fromthe standpoint of the ultimate product in -thatvthe leaves are non-uniformly dried and the quality .of the leaf is deleteriously affected. :More particularly, the edges -and exposed portions of thev leaves are overdried land the tobacco as a whole rendered of a non-uniform moisture content, which renders it unsatisfactory for fabrication and'productive of a. non-uniform and unsatisfactory'product from the standpoint ofquality.

'I'he disadvantages arising from'the procedures heretofore followedin reducing the moisture content of tobacco priorl to fabrication are, more particularly, disadvantageous in connection with the manufacture of cigars, whichare required, for maximum quality, to have 'a uniform moisture content within relatively narrow limits.

Now inaccordance with this invention a method for treating tobacco, and more particularly for The method in-accordance with this invention involves from the broad standpoint reductionin the moisture content of tobacco by subjecting the tobacco to a humid, heated atmosphere, and, more particularly, by passing the tobacco through a plurality of zones in which respectively the humidity and temperature varies.

More particularly, according to the method of this invention, the tobacco is passed irst through a zone of relatively high ltemperature and high humidity, in which only a restricted evaporation of'moisture occurs and in which the vapor p ressure of the moisture in the tobacco is raised, and

then through a plurality of zones at lowered hud midityand temperature and in which the vapor pressure of the air is low, to uniformly bring the moisture content of the tobacco down to the desired point.

still more particularly, the tobacco wm be passed in counteriow with air, lthe air being recirculate'd in the several zones. In other words,

theA air used for treatment of the tobacco in the iinal zone will pass progressively from zone to zone, with recirculation in each zone until finally l it will be used for'treatment of the tobacco in the initial zone.

this invention will The apparatus embodying comprise a chamber or tunnel. of relatively great lengthv in comparison toits width, having an inlet for airat one endend a discharge at its other end and provided with means whereby air'introduced at an end of the chamber will be recirculated in zones and, at the same time, have a longitudinal flow. I'he chamber will be adapted for the reception and passage of means carrying tobecco to be treated. More speciiic features of the method and apparatus will appear from the following more detailed description'thereof. A

.Having now indicated in a general way the nature and purpose of this invention, I will proceed to a more detailed description of a preferred form of apparatus for carrying out of the method, with reference to the following drawing, in which:

Figure 1 is a diagrammatic plan view of the apparatus in accordance with thislnvention.

Ii'igux'e 2 is a longitudinal detailview of the subject of Figure 1. v

Figure 31s a transverse detail view ofthe mbiect lof Figure 1. i j

Plgureiisa detail viewofsupportfortobacco. Figure 5 is a.,perspective view of a pad d stripped tobacco. -In the drawing a indicates an elongated chamber or tunnel, the ends of which are respective designated b and c.

The ends of the tunnel are provided with doorways, adapted to be closed by doors d, through which lines of track e extend longitudinally of the tunnel. As shown the tunnel contains four lines of track arranged in pairs on opposite sides of the central portion of the tunnel.

Air introduced at the end -b of the tunnel is passed longitudinally through the tunnel and discharged at the end c, and, at the same time, recircuited ina plurality of zones formed longitudinally of the tunnel by means of a plurality of encased fans f, driven by any suitable means, as motors g, receiving air from inlet chambers h, equipped with heating means y' connected with the fan oasings and provided with inlets opening into the tunnel andv discharging through conduits z extending longitudinally of the tunnel,

centrallythereof, toward the end c and provided with lateral outlets k. The heating means 7 are adapted to be controlled by.humidostat r positioned adjacent the inlets to chambers h, which responsive to the humidity in the several chambers, will operate to vary the supply of steam through conduits t, or to vary electric current supplied if the heating elements be electrical'. Steam jets s for the admission of steam to the chambers h for increasing relative humidity in theA chambers are also provided and adapted to be controlled by the humidostats` r.

'I'he -fan's f, inlet chambers h and conduits i are arranged progressively in the'upper portion of the tunnel from the end b adjacent to which the first fan is positioned and are of similar construction except that the inlet. chamber of the rst fan adjacent to" the end b of the tunnel l is connected to a conduit l leading from an outside supply of conditioned air and through which conditioned air is supplied tothe tunnel,`

The dischargeconduits i connected with the several encased fans f, while of the same struc-v ture, are of varying'length, depending upon the extent of the respective zones to be formed in the chamber'.

Adjacent to the end b of the tunnel a relief damper m, adapted to open automatically on the development of a predetermined pressure in the tunnel adjacent the end b, is provided; while a damper n, through which air is discharged from the tunnel, is provided adjacent to the end c of the tunnel. 'The operation of the damper n is arranged to be controlled automatically by mechanism (not shown) which is responsive to the relative humidity of the air in the tunnel adjacent to the end c.

Dampers n', n" and 11"', adapted to be controlled automatically, are arranged for the discharge of air from the several chambers X, Y and Z for control 0f the condition 'of relative humidity in the several chambers.

Tobacco to be treatedis introduced into the y tunnel at the end c and discharged atl theend b. The tobacco is thus passed through vthe tunnel in counterilow with respect to the vflow of air,

which, ashas been indicated, enters the tunnel tunnel will be filled with lines of trucks arranged end to end, as shown in Figure 2, and the trucks and supported tobacco will be removed progressively from 'the end b of the tunnel by intermittent movement of the lines as a unit through the operation of any suitable mechanism. As trucks are .removed from the tunnel at the end b, by a movement of the lines, respectively, as units corresponding space will be left for the entry of trucks intothe tunnelat the end c.

The passage of air longitudinally of the tunnel and its recirculation in zones progressively will be accomplished by the operation of the several fans f and the longitudinal extent of the several zones of recirculation will be determined by. the

lengths of the several discharge conduits i'.

Thus, the fan f adjacent the end b of the tunnel, will receive air through conduit l and will discharge it into the tunnel laterally through its conduit i, which has a limited extension longitudinally of the tunnel. At the same time air' will be drawn from the tunnel into the inlet chamber h of'the fan. Hence, a high pressure area will be built up in the zone of discharge from the conduit i and a low pressure area will be formed adjacent to the inlet from the tunnel to chamber h. The air discharged laterally from conduit z will have a rotary motion with respect to the tunnel and likewise a tendency to flow toward the low pressure area adjacent the inlet low pressure area adjacent the inlet to the chamber h of the second fan, and into the chamber and second fan for discharge through the second vconduit i and recirculation in a second zone as described. The several successive fans all operate in a similar manner with the formation of zones in which air is recirculated by the several fans with a rotary motion with, at the same time, formation of a spiral ow of air longitudinally of the chamber from the end b to the end c.

In the apparatus embodying this invention, as shown'in the accompanying drawing, and for practical adaptation of the method in accordance with this invention for the preparation of, for example, fillers or binders' for cigars, the elongated chamber or tunnel is divided into four zones designated, from the end c of the tunnel, as W, X, Y and Z.

The tobacco to be treated and containing, for example, as much as 35% of moisture, is entered at the end c of the tunnel into zone W, in which a relatively high 'temperature and high relative humidity is maintained. For examp1e,'the temperature in the z one W may be about 110 F.,

or within the range 100 F.110 F. and the relative humidity may be, for example, about cr within aboutthe range 70%-35%.

In the zone W very little moisture will be removed from the tobacco due to the high relative humidity of the air in that zone. The high y temperature in the zone W will, however, eiIect a heating of the tobacco and cause the evolution ofl ammonia therein, which will dissolve and carry out' of the tobacco any nicotine, oils and tars remaining therein, to a desired extent. In the zone W, while the evaporation of moisture from the tobacco will be restricted, a high vapor pressure within the tobacco leaves will be established.

The air circulated in zone W by the ian f controlling circulation in that zone, will be drawn, as described above, from the adjacent zone X. The air Withdrawn from zone X for circulation in zone W, will have a high relative humidity due to the absorption of moisture from the tobacco in zone X and the desired temperature of the air circulated in zone W and consequently desired relative humidity will be obtained through a heating of the air drawn from zone X prior to circulation in zone W, to a suitable temperature as determined by the set of the humidostat r. by the heating means y in the inlet chamber h of the fan f controlling the circulation in zone W.

The tobacco having been subjected to treat- Vment in zone W, the treatment involving essentiaily a heating up ofthe tobacco resultinginevolution of ammonia and generation of high vaporl pressure inthe leaf, will pass to the adjacent zone X,-in which a lower temperature and f lower relative humidity than prevails in zone W will be maintained.y By way of example, the temperature in zone X may be about 105 or Within about the range 95 F.105 F.and the relative humidity will be say about 60%.

In the zone X the vapor pressure of the air will be relatively low and evaporation of moisture from tobacco will occur.

From thezone X the tobacco will pass to the adjacent zoneY, in which the tempeature will be somewhat lower than in zone X, and in which the relative humidity may be 'substantially the same as in zone X. By way of example, the temperature of the air in zone Y may be about 100 F., or within about the range 80 F.105 F. In the zone Y evaporation of moisture from the tobacco will occur. YThe rate of evaporation will be controlled automatically by the automatic control of the relative humidity in vthe zones through control'of the heating means i or of the steam jets t by the humidostats r, and, indeed, evaporation'may be stopped if the tobacco is permitted to remain overlong in the zones.

In the zones X and Y the moisture content of the tobacco willI be reduced to and may be held at about the desired moisture content, which, by' way of example, may be a moisture content of about 17%18%, through control ofthe heating means by the humidostats r.

On leaving the 'zone Y the tobacco into the zone Z, in which a relatively low temperature compared to that in the zones X and Y will be maintained and in which a relative humidity substantially higher than that in zones X and Y will be maintained. Inthe zone Z, as in the zone W, evaporation of moisture from the tobacco will be restricted. In the zone. Z the tobacco will be cooled to a desired temperature and will be brought to a uniform moisture content.

In the zone Z the `temperature will be within about the relatively narrow range 75 F.85 F. and the relative humidity will be about 80%.

In the zone Z the tobacco will, as has beenindicated, be brought to a uniform desired moisture content. Thu the conditions in zone Z-will be such that if-th .tobacco passing into zone Z from zone Y contain'sksome excess moisture over that desired, excess will be evaporated in zone Z. Again, if the tobacco passing into zone Z have a moisture content somewhat below that desired, moisture will be added in zone Z. As will be appreciated, some parts of the tobacco entering zone Z may be deiicient in moisture, while some parts may contain'ifsorne excess moisture. In

will pass.

zone Z the tobacco will all be brought toa substantially uniform moisture content.

As will be appreciated, due to the flow of air longitudinally of the chamber or tunnel from the end b to the end c, the air,.in its passage through the several zones to the zone W, will pick up moisture. yThe desired relative humidity in the several zones including the zone W, will be obtained by control of the temperature by the heating means j associated with the several fans' f controlling the circulation in the several zones. The air introduced into the zone Z from conditioning means outside of the chamber or tunnel, will be initially a't substantially the humidity and temperature desired for the zone Z and since comparatively little evaporation of moisture will take place in the zone Z, the conditions desired therein will readily be maintained through maintenance of the desired temperature and/or humidity by the heating means, which may include a moistening device, asl steam jets s, associated with the fan controlling circulation irl-zone Z and under the 'control of humidostats r. It will be appreciated that such evaporation of moisture from tobacco as occurs in zone Z will tend to cool the air circulated therein and the temperature will be\maintained by the heating means.

As the air passes through zone Z to zone Y and is 'circulated therein, its temperature will be raised by the heating means associated with the fan controlling the circulation in zone Y. and consequently the relative humidity will be lowered, permittingevaporation of moisture from the tobacco.

As air passes from zone Y to zone X and is circulated in zone X, its relative humidity will remain substantially thesame as that obtaining in zone Y by virtue of the fact that the temperature of the air in zone X is raised by the heating means associated with the fan, which controls circulation. in zone X, to a temperature above that obtaining in zone Y.

The air circulated in zone X absorbs a further quantity o f moisture over that absorbed in zone Y, due to even greater evaporation of moisture from the tobacco than occurs in zone Y. .As a consequence, the air passing from zone X intov zone W is of a relatively high humidity and the increase in temperature of the air in zone W is controlled so that the desired high relative humidity for restricted evaporation of moisture from the tobaccoin zone W is obtained and, at

the same time, so as to obtain the necessary desired heating of the tobacco.

From the above description, it will now be apparent that in accordance withthe method embodying this invention tobacco is, as it were, counterowed with air through a plurality of zones formed by local circulation of air traveling generally in a direction opposite to that in which the tobacco travels and that the conditions in the several zones are such that in the iirst zone the tobacco is heated with evolution of ammonia and solution and carrying oi of nicotine oils, etc.` and the vapor pressure in the leaves is raised and evaporation of moisture from the tobacco is restricted, while in the last zone the moisture content of the tobacco is brought to uniformity and in intermediate zones the evaporation of moisture from the tobacco to about a desired content is effected.

As will be apparent, conditioned air is supplied to the final zone and passes from zone to zone, respectively, to the zone into which the tobacco y is initially entered so that the air used for m1- tial treatment of the tobacco is the same air as has been used for subsequent treatment, including evaporation of moisture, and effecting uniformity of moisture content. Thus: the air used to initially treat the tobacco under conditions of restricted evaporation is charged with the moisture evaporated from the tobacc'o in subsequent treating zones. The relative humidity of the air in the several zones is regulatedl by regulation of the temperature of the air, it being noted that the temperature decreases in the zones progressively from the initial. zone to the final zone, or conversely, increases from the final zone Cal to the initial zone. The relative humidity is lower in the intermediate zones, in which evaporation takes place, than in the initial zone and rises again in the final zone, in which, as in the initial zone, evaporation is restricted. 'Ihe high relative humidity condition obtaining in the initial zone is obtained in comparison with that obtaining in the final and intermediate zones by virtue of the absorption of moisture evaporated from the tobacco in the intermediate zones, in which, as has been indicated, the moisture content of the tobacco is reduced to about that desired.

In carrying out the method in accordance with this invention using the apparatus in accordance therewith, as has been indicated, tobacco will be initially entered into the zone W in the form of packs e comprising a plurality of superimposed leavespositioned on racks p, carried by trucks q.

The trucks carrying the tobacco 'will be'enteredinto zone W on the tracks e through doors d in the end c of the elongated chamber or tunnel. The tobacco will be permitted to remain in the zone W for the desired length of time'and will then be moved successively into the zones X, Y and Z, in each of which it will be permitted to remain for a sufiicient length of time to accomplish the purpose of evaporation and regulation to a uniform moisture content. As will be obvious, the lines of track in the chamber or tunnel will ultimately be filled with trucks carrying tobacco.

As the tobacco carried on the trucks adjacent to the doors d at the end b of the tunnel is in proper condition, from the standpoint of uniform moisture content, the trucks adjacent the end b will be removed by hand, from one or all of the lines of track. Then, by the operation of .any suitable mechanism, the line of trucks on the track or tracks from which a truck has been re-V moved will be advanced and a truck or trucks Will be entered by hand into the tunnel at the end c on the line or lines of tracks from which a truck or trucks has been removed at the end b of the tunnel. l

Any given truckload oftobacco will be permitted to remain in the tunnel for such time as is necessary to bring it to a uniform desired moisture content. The exact time of treatment will depend upon various factors, as, for" example, particular temperature and humidity, length of the tunnel as a whole, length of the several zones, respectively, and the like. It will be understood, however, that while for agiven lengthof tunnel and given conditions of humidity and temperature in the several zones a minimum timeof treatment Will be required, depending upon the moisture content of the tobacco when introduced into the tunnel and desired moisture content to be obtained, it will be understood that tobacco may remain in the chamber or tunnel for any time longer than the minimum required for obtaining the desired uniform moisture content,

since conditions in the nal zone Z will be such as not only to bring the tobaccoto a desired uniform moisture content, but to hold it-at desired moisture content, it being .notedjbat in the zone Z the conditions will be suchthat moisture may be evaporated from or..absorbed by the tobacco, depending upon the moisture content of the tobacco when it enters the zone Z with respect to y i for the carrying out of the method in accordance with this invention, for example, the chamber or tunnel may have a total length of 168 feet. Zone W may have a length of 60 feet, the zones X and Y a length of 40 feet each and the zone Z a length of 28 feet. With an apparatus of' such dimensions and assuming that tobacco is entered intolthe chamber or tunnel with a moisture content of about 35% and that it is desired to'reduce the v'moisture content to about 17% or 18%, and assuming a temperature in zone W of 110 F. and a relative humidity of 85%, a temperature in zone'l X of 105 F, and a relative humidity of 60%, a temperature of 100 F. in zone Y and' a relative humidity of 60% and a temperaturelof 75 F.78 F. 4in zone Z and a-relative humidity of 80%, the treating time in 'total' will 'be about 24 hours. During the treating period of about 24 hours the tobacco will remain in zone W for about 8 hours, 'in zone X for about 6 hours, in zone Y forabout 6 hours and may be removed from zone Z after about 4 hours therein. As nted, it will be indicated that the tobacco may .remain inthe zones for a longer period than 24 hours, -since the desired uniformininimum moisture'content will be obtained and will be maintained'i'n the zone X even though the tob acco bedesired to remain therein longer than such timeas may be necessary to Amaintain the desired uniform moisture content.

As will beappreciated, in the -operation ofthe apparatus there will be a tendency for pressure to develop in the zone Z. The development of any material pressure will be-prevented by virtue of the provision of damper m in the wall of the chamber or tunnel, which, as has been described, is arranged to open under pressure and will relieve any excess pressure which may develop. As has been indicated, discharge of air from the chamber or tunnel will be eiected through the discharge n provided in the wall of the tunnel adjacent the end c thereof in the zone W. Discharge from the tunnel `will be controlled by means of any suitable form of valve or damper controlling the discharge n and which will desirably be automatic in its operation and may, for example, be controlled by any suitable apparatus responsive to the relative humidity in the zone W.

It will also be appreciated that through contro of the humidostats of the heating means :i and/or of the steam jets s associated with the air circu lating system in each of the zones, and/or through control of the dampers n, n', n" and n" in each of the zones the proper conditions of relative humidity for desired evaporation of moisture from' the tobacco will be readily automatically maintained. At the same time, by virtue of the automatic controll exercised by the humidostats r, if the tobacco is permitted to remain in any zone for a period such that it would tend to lose moisture beyond theA amount desired to be lost, the relative humidity will be regulated to such as to negative evaporation.

It will be understood that it is not contemplated that this invention, either from the standpoint of method or apparatus, shall be limited by the detailed description given herein for purposes of illustration and exemplification, it being understood that modification and variation in detail, such as temperatures, relative humidities, time of treatment, dimensions of the chamber, or tunnel, dimensions and number of zones, particular apparatus for effecting circulating of air, etc., may be made without departing from the invention,

What I claim and desire to protect by Letters Patent is:

1. The method of treating tobacco to prepare it for use in the manufacture of cigars which comprises subjecting tobacco in a moist state to an atmosphere at a temperature within about the range 100-110" F. and having a relative humidity within about thel range 'T0-85% and then subjecting the tobacco to an atmosphere at a lower temperature Within about the range 95- tlg F. and having a relative humidity of about 2. The method of treating tobacco to prepare it for use in the manufacture of cigars which comprises subjecting tobacco in a moist state to an atmosphere at a temperature within about the range 10G-110 F. and having a relative humidity within about the range 'I0-85%, then subjecting the tobacco to an atmosphere at a lower temperature within about the range S35-105 F. and having a relative humidity of about and nally subjecting the tobacco to an atmosphere at a temperature Within about the range Z5-80 F. and having a relative humidity of about 3. The method of treating tobacco which comprises rst subjecting tobacco while in a moist state and at room temperature to a preliminary treatment in an atmosphere at a temperature such as to heat the tobacco and cause evolution of ammonia therein and having a relative humidity below and such as to prevent deposition of moisture on the tobacco and minimize the evaporation of moisture from the tobacco and then subjecting the tobacco to an atmosphere at a temperature and having a relative humidity such as to promote the evaporation of moisture from the tobacco and while the tobacco retains a substantial amount of moisture subjecting the tobacco to an atmosphere at a temperature and having a relative humidity such as to regulate the moisture content of the tobacco to a predetermined amount of moisture.

4. The method of treating tobacco which comprises iirst subjecting tobacco while in a moist state and at room temperature to a preliminary treatment in an atmosphere at a temperature such as to heat the tobacco and cause evolution of ammonia therein and having a relative hunudity below 100% and such as to prevent deposition of moisture on the tobacco and minimize the evaporation of moisture from the tobacco and then subjecting the tobacco to an atmosphere at a temperature and having a relative humidityu such as to promote the evaporation of moisture from the tobacco and nally subjecting the tobacco to an atmosphere at a temperature and having a. relative humidity below 100% and such as to minimize the evaporation of moisture from the tobacco and such as to bring the tobacco to a substantially uniform moisture content.

5. 'I'he method of treating tobacco which comprises moving tobacco carrying moisture through a plurality of successive zones in an unrestricted pass and including a preliminary treating zone, a nal zone and an intermediate zone or zones, while counterowing'air through the zones successively in a direction opposite to the direction of movement of the tobacco, the flow of air being spiral and the air being recirculated locally in the zones respectively, the tobacco being moist and at room temperature on entry into the preliminary treating zone and the temperature ofthe air in the preliminary treating zone rst entered by the tobacco being such as to heat the tobacco and cause the evolution of ammonia therein and the relative humidity of the air in side zone being below 100% and such as to prevent deposition of moisture on the tobacco and minimize -the evaporation of moisture yfrom tobacco, the air in the nal zone entered by the tobacco beingl at a temperature lower than the air in the preceding zones and the relative humidity of the air in Y zone.

RUSH D. TOUTON. 

